SOLUTION
After trying and reading a lot I find out a solution by accident…. I try to use a solution posted HERE making a modification to the .htaccess file on the root. It was a tutorial by dwdallam member. Follow the link to check it right without any modification.
Then I change the site url in Settings -> General (home was showing other pages and post don’t) so I COPY the index.php file in root (still with the problem) So I updated the permalinks…. (still with the problem) I went to check the .htaccess root file and it had the regular code at the end in which I had the subdirectory where the wordpress is installed…. (I don’t know If I forgot to erase it when I was coping the tutorial or it added by itself when I updated the permalinks)
My Final .htaccess looks like (replace for your own web site address and subdirectory)
# Change ‘YOURWEBSITE.COM’ to be your main domain.
RewriteCond %{HTTP_HOST} ^(www.)?YOURWEBSITE.COM$
# Change ‘YOURSUBDIRECTORY’ to be the directory you will use for your main domain.
RewriteCond %{REQUEST_URI} !^/YOURSUBDIRECTORY/
# Don’t change these line.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# Change ‘WP’ to be the directory you will use for your main domain.
RewriteRule ^(.*)$ /YOURSUBDIRECTORY/$1
# Change ‘YOURWEBSITE.COM’ to be your main domain again.
# Change ‘YOURSUBDIRECTORY’ to be the directory you will use for your main domain
# followed by / then the main file for your site, index.php, index.html, etc.
RewriteCond %{HTTP_HOST} ^(www.)?YOURWEBSITE.COM$
RewriteRule ^(/)?$ YOURSUBDIRECTORY/index.php [L]
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /YOURSUBDIRECTORY/
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /YOURSUBDIRECTORY/index.php [L]
</IfModule>
# END WordPress
now is working perfectly… Thanks for your help and I post the solution in case anyone has the same problem.